Hello,
I've run the R65 under -10°C. And never had this problem even if i use 20W50 oil all year long. (I use the bike everyday, rain or shine. The only rest she got is when I'm on vacation and/or snow)).
Maybe your filter maker was a poor one ? And the filter was sub-standard ?
I do stick to the Malhe/Knecht filters. (apparently, Knecht is/was bought by Mahle ? So both are the very same).